"We have maintained an Embassy in Damascus despite the violence to help us communicate with all parties in Syria and to provide insight into the situation on the ground. Throughout this time we have kept the security situation of our staff and Embassy premises under intense and constant review. We now judge that the deterioration of the security situation in Damascus puts our Embassy staff and premises at risk, and have taken the decision to withdraw staff accordingly."

"If we are going to succeed it is extremely important that we all accept that there should be one process of mediation."

It comes as Number 10 said David Cameron will raise Syria at Thursday's European Council summit in Brussels.

"Clearly, thousands of people are losing their lives in this terrible situation. Any way forward has got to be through peaceful means. We have got sanctions in place and we want to make sure that those people who have committed atrocities and crimes face up to those crimes," a Downing Street spokesperson said.